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采用受控扩散凝固技术(CDS)制备过共晶Al-18Si、Al-20Si、Al-22Si合金,研究了不同混合方式及Al-25Si合金在不同过热温度下对受控扩散凝固目标合金初生Si相的尺寸、形貌和分布的影响。结果表明,液-液混合对初生Si的改善效果较液-固混合好;随着过热温度增大,初生Si相尺寸减小,形貌逐渐变得圆整且分布均匀;相同过热温度下,随着合金Si含量的增加,初生Si相尺寸增大,形貌变化不明显。特别是在过热温度为900℃的Al-25Si合金与660℃的液态纯Al液-液混合得到Al-18Si合金中的初生Si相尺寸仅为34.3μm,长宽比为1.48。
Hypereutectic Al-18Si, Al-20Si and Al-22Si alloys were prepared by controlled diffusion solidification (CDS). The effects of different mixing methods and Al-25Si alloys on the controlled diffusion and solidification of target Si Phase size, morphology and distribution of the impact. The results show that the liquid-liquid mixture has a better effect on improving the primary Si than the liquid-solid. As the superheating temperature increases, the size of the primary Si phase decreases and the morphology gradually becomes round and evenly distributed. Under the same superheating temperature, With the increase of Si content, the size of primary Si phase increases and the morphology does not change obviously. In particular, Al-25Si alloy superheated at 900 ℃ and Al liquid-liquid at 660 ℃ were mixed to obtain Al-18Si alloy. The size of primary Si phase was only 34.3μm and the aspect ratio was 1.48.